1. Field of the Invention
The present invention relates to a stentless artificial mitral valve and artificial valve leaflet, and template and cutter for forming the artificial valve leaflet, and more particularly, to a stentless artificial mitral valve, and artificial valve leaflet which are implanted into the heart on the occasion of valve replacement for valvular disease of heart or the like, capable of realizing valve behavior similar to a real mitral valve.
2. Description of the Related Art
Of the human heart valves, the mitral valve is a unidirectional valve located between the left atrium into which the blood from the lung flows and the left ventricle that sends out the blood flown into the left atrium to the whole body, made up of two valve leaflets called “anterior cusp” and “posterior cusp,” and is different in structure from other heart valves such as the aortic valve made up of three valve leaflets. The anterior cusp and posterior cusp of the mitral valve are located within an annular portion called “valve annulus” and connected to the wall of the left ventricle via a string-like tendinous cord. Here, the interior of the left ventricle is held in a positive pressure state in a contraction phase of the heart and the anterior cusp and posterior cusp come into close contact, producing a closed valve state, whereas in a diastolic phase of the heart, the interior of the left ventricle is held in a negative pressure state and the anterior cusp and posterior cusp are mutually pulled, producing an open valve state.
One of the remedies for a patient suffering from mitral regurgitation with the mitral valve disabled by a lesion and the blood flowing backward from the left ventricle to the left atrium is artificial valve replacement whereby the lesioned mitral valve is removed and replaced by an artificial valve.
A so-called prosthetic valve is known as such an artificial valve formed using a biological tissue of swine or the like and International Publication No. WO2005-067821 discloses two artificial valves made up of a biological tissue. The document discloses two types of artificial valve; a stent artificial valve having a frame called “stent” and a stentless artificial valve with no stent. The former stent artificial valve is constructed of a stent made of a wire and constituting the outside shape of the artificial valve, and first and second valve leaflets joined to the stent. Here, the first and second valve leaflets are provided so as to be cloak-shaped when planar expanded and is formed of a biological tissue resected from the aortic valve of swine. On the other hand, the latter stentless artificial valve is created by sewing the first and second valve leaflets to the inner surface of a tubular body made up of a biological tissue.